Fair Value Disclosures - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Income	Net Income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 7,632,487	$ 6,358,451
Purchases	687,650	832,750
Settlements	(142,437)	(296,870)
Allowance for Losses	36	(416)
Realized and unrealized gains included in Income	93,701	(210,494)
Unrealized (losses)/gains included in Other Comprehensive Income	(20,977)	(54,690)
Ending Balance	8,250,460	6,628,731
Floating rate auction-rate certificates backed by Government guaranteed student loans \| Floating Interest Rate \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,027	19,254
Purchases	0	0
Settlements	0	0
Allowance for Losses	4	2
Realized and unrealized gains included in Income	0	0
Unrealized (losses)/gains included in Other Comprehensive Income	0	(295)
Ending Balance	19,031	18,961
Available-for-sale securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,027	19,254
Purchases	0	0
Settlements	0	0
Allowance for Losses	4	2
Realized and unrealized gains included in Income	0	0
Unrealized (losses)/gains included in Other Comprehensive Income	0	(295)
Ending Balance	19,031	18,961
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,607,226	6,328,559
Purchases	687,650	832,750
Settlements	(141,819)	(295,663)
Allowance for Losses	32	(418)
Realized and unrealized gains included in Income	93,342	(210,587)
Unrealized (losses)/gains included in Other Comprehensive Income	(20,977)	(54,395)
Ending Balance	8,225,454	6,600,246
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| AgVantage Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,599,379	6,316,145
Purchases	687,650	832,750
Settlements	(141,386)	(295,284)
Allowance for Losses	32	(418)
Realized and unrealized gains included in Income	93,342	(210,587)
Unrealized (losses)/gains included in Other Comprehensive Income	(21,597)	(53,382)
Ending Balance	8,217,420	6,589,224
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,847	12,414
Purchases	0	0
Settlements	(433)	(379)
Allowance for Losses	0	0
Realized and unrealized gains included in Income	0	0
Unrealized (losses)/gains included in Other Comprehensive Income	620	(1,013)
Ending Balance	8,034	11,022
USDA Securities: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,767	4,401
Purchases	0	0
Settlements	(387)	(952)
Allowance for Losses	0	0
Realized and unrealized gains included in Income	25	(63)
Unrealized (losses)/gains included in Other Comprehensive Income	0	0
Ending Balance	1,405	3,386
Guarantee and commitment obligations: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,467	6,237
Purchases	0	0
Settlements	(231)	(255)
Allowance for Losses	0	0
Realized and unrealized gains included in Income	334	156
Unrealized (losses)/gains included in Other Comprehensive Income	0	0
Ending Balance	4,570	6,138
Guarantee and commitment obligations: \| Level 3 \| Recurring \| Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,467	6,237
Purchases	0	0
Settlements	(231)	(255)
Allowance for Losses	0	0
Realized and unrealized gains included in Income	334	156
Unrealized (losses)/gains included in Other Comprehensive Income	0	0
Ending Balance	$ 4,570	$ 6,138

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Allowance for Credit Loss

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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Indicates line item in statement in which other comprehensive income (OCI) is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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